The proposed studies will continue our probe of the relationship between the rat liver steroid sulfotransferases--STI, STII, and STIII--and the actions of glucocorticoids typified by cortisol. During the course of the studies envisioned for this year, we hope to complete purification and characterization of STI and STIII; prepare antisulfotransferases and use the purified antibodies to develop a rapid immunochemical method for determination of tissue STI, STII, and STIII levels; examine the relationship between the mineralocorticoid sulfotransferase and cortisol Binder IB; examine the relationship between streptozetocin diabetes, the sulfotransferases, and hypertension. (A) Our 2,000-fold purified STIII appears to be homogeneous. It will be used to prepare anti-STIII. This will be tested for specificity against STI, STII, and STIII. (B) If anti-STIII is monospecific, we will prepare anti-STI as soon as we complete purification of our highly purified STI preparation. (C) Purification of STI will use several new affinity matrices to be prepared. (D) Finalization of STI and STIII characterization will be carried out if both preparations are sufficiently pure to justify this. These studies will include mechanistic determination, active site studies, subunit structure determination, and other physiocochemical parameters. (E) The basis for the stimulatory and inhibitory effects of biologically significant metal ions on STI and STIII will be addressed. (F) Study of the effect of streptozotocin (Sz) diabetes on the sulfotransferases will continue. Its enzymatic basis, reversibility by insulin, and the relation to Sz-induced hypertension will be examined. (G) Study of the properties of the mineralocorticoid sulfotransferase will be undertaken and its relation to Binder IB will be examined.